1. Field of the Invention
The present invention pertains to an excavating bucket or dipper having a lightweight replaceable section comprising the lower sidewalls and bottom wall of the bucket and a lightweight reinforced dump door.
2. Background
Excavating devices such as a power shovel dippers and dragline buckets must have adequate strength to withstand the high forces exerted thereon during excavating and carrying functions as well as resisting abrasive wear by the material being excavated. However, the weight of material required to provide adequate strength and life in the dipper or bucket reduces the effective payload of excavating apparatus such as power shovels or draglines.
In the excavation and loading of most materials, the payload per operating cycle and the number of operating cycles per unit time is of economic importance. If, for example, the payload per operating cycle of load-dump-prepare to load is increased, the operating cycle time can be reduced or the effective production of the shovel or dragline per unit time may be increased. This increased production in some applications of excavating machines such as the high volume production of coal and various minerals may easily offset the cost of more frequent replacing of the bucket or at least portions thereof. In this regard, the present invention is directed to providing a lightweight high-capacity excavating bucket or dipper having a replaceable section which may be easily replaced in the field and may yield a net increase in economic benefits. That is, the added production of the material excavated over a given amount of time may provide more revenue than the cost of replacing the replaceable section of the bucket.
Prior art excavating bucket and dipper designs have evolved as heavy, cast and welded structures or somewhat built-up structures of plate and welded reinforcements. In both instances, the entire bucket or dipper structure must be replaced when worn. Although the lower and sidewall portions of an excavating bucket are subject to the most wear and tear, these portions are not easily replaced or reconditioned in prior art excavating buckets. In this regard the present invention provides an improved bucket or dipper design which provides for field replacement of a section of the bucket which is subject to the greatest amount of wear, thereby providing a so-called throw-away portion or section of the bucket or dipper and which is lightweight so as to increase the effective payload of the bucket and/or by providing the bucket as a somewhat larger capacity device for the given capacity rating of a shovel or dragline so that the net payload per operating cycle of the machine may be increased.